The influence of orientation on electromagnetic properties of basalt fibre/nickel core-shell heterostructures prepared by a simple electroless plating method is investigated. For comparison, the same investigation is ...The influence of orientation on electromagnetic properties of basalt fibre/nickel core-shell heterostructures prepared by a simple electroless plating method is investigated. For comparison, the same investigation is also performed on naked basalt fibres. For electromagnetic measurement, the directions of basalt fibre/nickel and naked basalt fibres are parallel, random and perpendicular to the direction of external electric field, termed E11 sample, random sample and E⊥ sample, respectively. Electromagnetic anisotropy can be clearly observed in the basalt fibre/nickel core-shell heterostructures, while electromagnetic properties of naked basalt fibres are unrelated to the orientation. The E⊥ basalt fibre/nickel shows the highest dielectric loss but the lowest magnetic loss, and E11 basalt fibre/nickel exhibits the highest magnetic loss but the lowest dielectric loss. The dielectric loss of E⊥ basalt fibre/nickel is several times as large as that of Eli basalt fibre/nickel, which could be attributed to the increase of polarization relaxation time as a consequence of the nanosize-confinement effect. The magnetic loss of E11 basalt fibre/nickel is even one order of magnitude higher than that of E⊥ basalt fibre/nickel, which originates mainly from the natural magnetic resonance of basalt fibre/nickel core-shell heterostructures.展开更多
Dielectric properties of SiC/Ni nanocomposites prepared by a simple and facile electroless plating approach at X band are investigated. Compared to the original SiC nanopartieles （SiCp）, the real part of the permitt...Dielectric properties of SiC/Ni nanocomposites prepared by a simple and facile electroless plating approach at X band are investigated. Compared to the original SiC nanopartieles （SiCp）, the real part of the permittivity, ε＇, and the dielectric loss tangent tang δe of SiC/Ni nanocomposites are clearly enhanced by about 31% and 33%, respectively. The effective equations for complex permittivity of SiC/Ni nanoeomposites are proposed. We also calculate ε＇ and tan δe of SiC/Ni nanoeomposites and the calculated results are well consistent with the measured data.展开更多
Ni-deposited SiC particles are prepared successfully by a facile chemical reaction approach. The structure and morphology analyses demonstrate the Ni nanoparticles have been deposited on the surface of SiC particles. ...Ni-deposited SiC particles are prepared successfully by a facile chemical reaction approach. The structure and morphology analyses demonstrate the Ni nanoparticles have been deposited on the surface of SiC particles. The deposition behavior of Ni on the surface of SiC particles is investigated. Pd-Sn catalytic nuclei formed in the pretreatment process promote the redox reaction and lead to the reduction of Ni^2＋ to metal nickel. Moreover, the kinetic mechanism of the reaction process of Ni%2＋ and H2PO^-2 has also been discussed in detail. Kinetic models have been established.展开更多
Bi_(0.95)_(0.05)FeO_(3)nanocrystals are synthesized by a hydrothermal method,and are crystallized in a rhombohedrally distorted perovskite BiFeO_(3)structure in the R3c space,with compressive lattice distortion induce...Bi_(0.95)_(0.05)FeO_(3)nanocrystals are synthesized by a hydrothermal method,and are crystallized in a rhombohedrally distorted perovskite BiFeO_(3)structure in the R3c space,with compressive lattice distortion induced by the Y substitution at Bi sites from XRD study Compared with BiFeO_(3)gained under similar conditions,the magnetic properties are greatly enhanced,with saturate magnetization of 2.3emu/g at room temperature.Microwave dielectric properties of Bi0.95 Y0.05FeO_(3)nanocrystals are investigated in the range of 2-18 GHz.The Y substitution results in the increase of permeability and decrease of permittivity which are attributed to the enhanced spin relaxation of domain wall motion and the weakened electron-relaxation caused by decreasing Fe^(2+),respectively.The changes for microwave dielectric response could lead to the excellent microwave absorption due to the improvement of the impedance match between BiFeO_(3)and air.展开更多
We study the mechanism of microwave response properties of SiCv/paraffin nanocomposites and propose a mi- crowave absorption model of nanocomposites based on the conservation law of energy and the theory of electro- m...We study the mechanism of microwave response properties of SiCv/paraffin nanocomposites and propose a mi- crowave absorption model of nanocomposites based on the conservation law of energy and the theory of electro- magnetic scattering. Using the model we calculate the reflectivity of SiCp/paraffin nanocomposites ranging from 2 GHz to 18 GHz. The calculated results are very consistent with the experimental data in the frequency range investigated.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 50872159)the National Defense Pre-Research Foundation of China (Grant Nos. 513180303 and A2220061080)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 2004007021)
文摘The influence of orientation on electromagnetic properties of basalt fibre/nickel core-shell heterostructures prepared by a simple electroless plating method is investigated. For comparison, the same investigation is also performed on naked basalt fibres. For electromagnetic measurement, the directions of basalt fibre/nickel and naked basalt fibres are parallel, random and perpendicular to the direction of external electric field, termed E11 sample, random sample and E⊥ sample, respectively. Electromagnetic anisotropy can be clearly observed in the basalt fibre/nickel core-shell heterostructures, while electromagnetic properties of naked basalt fibres are unrelated to the orientation. The E⊥ basalt fibre/nickel shows the highest dielectric loss but the lowest magnetic loss, and E11 basalt fibre/nickel exhibits the highest magnetic loss but the lowest dielectric loss. The dielectric loss of E⊥ basalt fibre/nickel is several times as large as that of Eli basalt fibre/nickel, which could be attributed to the increase of polarization relaxation time as a consequence of the nanosize-confinement effect. The magnetic loss of E11 basalt fibre/nickel is even one order of magnitude higher than that of E⊥ basalt fibre/nickel, which originates mainly from the natural magnetic resonance of basalt fibre/nickel core-shell heterostructures.
文摘Dielectric properties of SiC/Ni nanocomposites prepared by a simple and facile electroless plating approach at X band are investigated. Compared to the original SiC nanopartieles （SiCp）, the real part of the permittivity, ε＇, and the dielectric loss tangent tang δe of SiC/Ni nanocomposites are clearly enhanced by about 31% and 33%, respectively. The effective equations for complex permittivity of SiC/Ni nanoeomposites are proposed. We also calculate ε＇ and tan δe of SiC/Ni nanoeomposites and the calculated results are well consistent with the measured data.
基金Supported by the National Natural Science Foundation of China under Grant No 50972015, the National Defense Funds of China under Grant Nos 513180303 and A2220061080, the Doctoral Fund of Ministry of Education of China under Grant No 2004007021 for providing, and the Scientific and Technological Project of Heilongjiang under Grant No GC06A208.
文摘Ni-deposited SiC particles are prepared successfully by a facile chemical reaction approach. The structure and morphology analyses demonstrate the Ni nanoparticles have been deposited on the surface of SiC particles. The deposition behavior of Ni on the surface of SiC particles is investigated. Pd-Sn catalytic nuclei formed in the pretreatment process promote the redox reaction and lead to the reduction of Ni^2＋ to metal nickel. Moreover, the kinetic mechanism of the reaction process of Ni%2＋ and H2PO^-2 has also been discussed in detail. Kinetic models have been established.
基金Supported by the National Natural Science Foundation of under Grant No 50872159,and the Physics Development Fund of BUCT.
文摘Bi_(0.95)_(0.05)FeO_(3)nanocrystals are synthesized by a hydrothermal method,and are crystallized in a rhombohedrally distorted perovskite BiFeO_(3)structure in the R3c space,with compressive lattice distortion induced by the Y substitution at Bi sites from XRD study Compared with BiFeO_(3)gained under similar conditions,the magnetic properties are greatly enhanced,with saturate magnetization of 2.3emu/g at room temperature.Microwave dielectric properties of Bi0.95 Y0.05FeO_(3)nanocrystals are investigated in the range of 2-18 GHz.The Y substitution results in the increase of permeability and decrease of permittivity which are attributed to the enhanced spin relaxation of domain wall motion and the weakened electron-relaxation caused by decreasing Fe^(2+),respectively.The changes for microwave dielectric response could lead to the excellent microwave absorption due to the improvement of the impedance match between BiFeO_(3)and air.
文摘We study the mechanism of microwave response properties of SiCv/paraffin nanocomposites and propose a mi- crowave absorption model of nanocomposites based on the conservation law of energy and the theory of electro- magnetic scattering. Using the model we calculate the reflectivity of SiCp/paraffin nanocomposites ranging from 2 GHz to 18 GHz. The calculated results are very consistent with the experimental data in the frequency range investigated.
